71M6511 Datasheet, PDF (40/95 Pages) Teridian Semiconductor Corporation – Single-Phase Energy Meter IC

71M6511/71M6511H
Single-Phase Energy Meter IC
DATA SHEET
AUGUST 2007
COM0
COM1
COM2
COM3
Dedicated Segment Pins
Shared w/ DIO4-DIO11 Shared w/ DIO14-DIO17
SEG0 SEG1 … SEG19 SEG24 … SEG31 SEG34 … SEG37
P0
P4
…
P76
P80 … P108 P112 … P124
P1
P5
…
P77
P81 … P109 P113 ...
P125
P2
P6
…
P78
P82 … P110 P114 … P126
P3
P7
…
P79
P83 … P111 P115 … P127
Table 56: Liquid Crystal Display Segment Table (Typical)
Note: P0, P1, … Represent the pixel/segment numbers on the LCD.
A charge pump suitable for driving VLCD is included on-chip. This circuit creates 5V from the 3.3V supply. A contrast DAC is
provided that permits the LCD full-scale voltage to be adjusted between VLCD and 70% of VLCD. The LCD_NUM register
defines the number of dual purpose pins used for LCD segment interface.
LCD Voltage Boost Circuitry
A voltage boost circuit may be used to generate 5V from the 3.3V supply to support low-power 5V devices, such as LCDs.
Figure 10 shows a block diagram of the voltage boost circuitry including the voltage regulators for V2P5 and V2P5NV. When
activated using the I/O RAM register LCD_BSTEN (0x2020[7]), the boost circuitry provides an AC voltage at the VDRV output
pin (see the Applications section for details).
VOLTAGE
BOOST
LCD_IBST
LCD_BSTEN
V2P5NV
GNDD
V3P3D
VDRV
GNDD
VOLT
REG
0.1V
V2P5
V3P3D
VBAT
GNDD
GNDD
V2P5
VLCD
Figure 10: LCD Voltage Boost Circuitry
UART (UART0) and Optical Port (UART1)
The 71M6511/6511H includes an interface to implement an IR or optical port. The pin OPT_TX is designed to directly drive an
external LED for transmitting data on an optical link (low-active). The pin OPT_RX, also low-active, is designed to sense the
input from an external photo detector used as the receiver for the optical link. These two pins are connected to a dedicated
UART port. OPT_TX can be tristated if it is desired to multiplex another I/O pin to the OPT_TX output. The control bit for the
OPT_TX output is the I/O RAM register OPT_TXDIS (0x2008[5]).
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